There have conventionally been known vehicle driving systems which include an internal combustion engine, an electric motor and auxiliaries such as an air conditioner compressor and a lubrication pump (for example, refer to Patent Literature 1).
A vehicle driving system 200 of Patent Literature 1 includes, as shown in FIG. 9, a dual-clutch type transmission mechanism which includes: a first input shaft 202a which is connected to an electric motor 210 and which is selectively connected to an internal combustion engine output shaft 204 by a first engaging and disengaging means 205; a second input shaft 202b which is selectively connected to the internal combustion engine output shaft 204 by a second engaging and disengaging means 206; an output shaft 203 which outputs power to a driven portion; a first gear train including plural gears which are electively connected to the first input shaft 202a via first synchromesh units 230, 231 which are disposed on the first input shaft 202a; a second gear train including plural gears which are selectively connected to the second input shaft 202b via second synchromesh units 216, 217 which are disposed on the second input shaft 202b; and a third gear train which is disposed on the output shaft 203 and which includes plural gears which mesh with the gears of the first gear train and the gears of the second gear train. The electric motor 210 includes a rotor 209 which has a rotor shaft 209a and a stator 211. In this vehicle driving system 200, an auxiliary 260 such as a lubrication pump or the like is connected to the rotor shaft 209a via a belt unit 262.